However, diseases or malformations affect proper operation of the valves.
In particular, the latter may suffer from calcification thus allowing backflow or regurgitation into the ventricle or atrium having expelled the blood flow. The regurgitation problem leads to abnormal expansion of the ventricle which finally produces heart failure. In certain cases, the valve comprises a number of leaflets smaller than the one generally observed for this type of valve, which may be detrimental to its operation in the long run.
In order to treat this type of disease in a surgical way, implantation of an endovalve between the leaflets of the affected native valve is known. This endovalve comprises a tubular endoprosthesis formed by a self-extensible trellis and a flexible obturator or valve most often made in a tissue of animal origin. The flexible obturator is permanently fixed in the endoprosthesis.
Such endovalves are implantable via an endolumen route, which considerably limits the risks associated with the implantation of the valve, notably in terms of mortality.
In certain cases, the endovalves do not give entire satisfaction after their implantation. Indeed, although the outer surface of the endoprosthesis is spontaneously applied against the seat of the native valve, flattening the leaflets between the seat and the outer surface of the endoprosthesis, leaks may subsist around the outer surface of the endoprosthesis, notably at the commissures defined between the leaflets of the native valve. These leaks occur in more than 50% of the patients having been subject to such an operation.
In order to overcome this problem, US 2005/0283231 describes an implant comprising an endoprosthesis and a prosthetic valve fixed in the endoprosthesis. The leaflets of the prosthetic valve of the endoprosthesis are extended with foldable segments around the endoprosthesis so as to be interposed between the wall of the conduit and the outer surface of the endoprosthesis. These folded segments around the endoprosthesis are able to at least partly fill the leaks which may occur around the valve.